Regional Forecasts

Atmospheric River Bringing Heavy Rain, Mountain Snow to the Pacific Northwest This Weekend

Cascade Snow To Be Measured In Feet

A pattern change has taken shape over the Pacific Northwest that is soaking Washington and Oregon this weekend.

Right on cue as we progress deeper into fall, the Pacific jet stream has begun to steer storm systems into the Pacific Northwest.

A classic atmospheric river event is affecting the Northwest this weekend.

An atmospheric river is a thin and long plume of moisture that stretches from the tropics or subtropics into higher latitudes – in this weekend's case, from the western Pacific Ocean to the northwestern United States. This is shown in the map above by the tongue of yellow and orange contours stretching toward the Pacific Northwest.

(MORE: Atmospheric Rivers: A Blessing and a Curse)

Current Satellite, Pressure and Atmospheric Moisture
(The light blue lines are isobars, or lines of equal pressure. The more numerous and tightly packed the isobars, the stronger the winds. Deeper atmospheric moisture is shown by yellow, orange and red contours.)

Lees Camp in northwest Oregon had picked up 9.3 inches of rain in just 24 hours as of early Sunday morning.

Some minor or moderate river flooding could develop in the most flood-prone rivers in western Washington and Oregon. The Wilson River near Tillamook, Oregon, reached moderate flood stage early Sunday.

Additional rainfall of 1-3 inches is possible Sunday before the atmospheric river event winds down.

(MAPS: Weekly Planner)

A break from this barrage of stormy weather will arrive in the Northwest early next week as the jet stream lifts northward and forces the storm track into Canada for a brief time.